1 /*
2 * Copyright (c) 2012, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23
24
25 package org.graalvm.compiler.hotspot.replacements;
26
27 import static jdk.vm.ci.code.MemoryBarriers.LOAD_STORE;
28 import static jdk.vm.ci.code.MemoryBarriers.STORE_STORE;
29 import static org.graalvm.compiler.hotspot.GraalHotSpotVMConfig.INJECTED_VMCONFIG;
30 import static org.graalvm.compiler.hotspot.nodes.BeginLockScopeNode.beginLockScope;
31 import static org.graalvm.compiler.hotspot.nodes.EndLockScopeNode.endLockScope;
32 import static org.graalvm.compiler.hotspot.nodes.VMErrorNode.vmError;
33 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.DISPLACED_MARK_WORD_LOCATION;
34 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.MARK_WORD_LOCATION;
35 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.OBJECT_MONITOR_CXQ_LOCATION;
36 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.OBJECT_MONITOR_ENTRY_LIST_LOCATION;
37 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.OBJECT_MONITOR_OWNER_LOCATION;
38 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.OBJECT_MONITOR_RECURSION_LOCATION;
39 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.PROTOTYPE_MARK_WORD_LOCATION;
40 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.ageMaskInPlace;
41 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.biasedLockMaskInPlace;
42 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.biasedLockPattern;
43 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.config;
44 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.epochMaskInPlace;
45 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.loadWordFromObject;
46 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.lockDisplacedMarkOffset;
47 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.markOffset;
48 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.monitorMask;
49 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.objectMonitorCxqOffset;
50 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.objectMonitorEntryListOffset;
51 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.objectMonitorOwnerOffset;
52 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.objectMonitorRecursionsOffset;
53 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.pageSize;
54 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.prototypeMarkWordOffset;
55 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.registerAsWord;
56 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.unlockedMask;
57 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.useBiasedLocking;
58 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.verifyOop;
59 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.wordSize;
60 import static org.graalvm.compiler.hotspot.replacements.HotspotSnippetsOptions.ProfileMonitors;
61 import static org.graalvm.compiler.hotspot.replacements.HotspotSnippetsOptions.SimpleFastInflatedLocking;
62 import static org.graalvm.compiler.hotspot.replacements.HotspotSnippetsOptions.TraceMonitorsMethodFilter;
63 import static org.graalvm.compiler.hotspot.replacements.HotspotSnippetsOptions.TraceMonitorsTypeFilter;
64 import static org.graalvm.compiler.hotspot.replacements.HotspotSnippetsOptions.VerifyBalancedMonitors;
65 import static org.graalvm.compiler.nodes.extended.BranchProbabilityNode.FAST_PATH_PROBABILITY;
66 import static org.graalvm.compiler.nodes.extended.BranchProbabilityNode.FREQUENT_PROBABILITY;
67 import static org.graalvm.compiler.nodes.extended.BranchProbabilityNode.NOT_FREQUENT_PROBABILITY;
68 import static org.graalvm.compiler.nodes.extended.BranchProbabilityNode.NOT_LIKELY_PROBABILITY;
69 import static org.graalvm.compiler.nodes.extended.BranchProbabilityNode.SLOW_PATH_PROBABILITY;
70 import static org.graalvm.compiler.nodes.extended.BranchProbabilityNode.VERY_FAST_PATH_PROBABILITY;
71 import static org.graalvm.compiler.nodes.extended.BranchProbabilityNode.probability;
72 import static org.graalvm.compiler.replacements.SnippetTemplate.DEFAULT_REPLACER;
73
74 import java.util.List;
75
76 import org.graalvm.compiler.api.replacements.Fold;
77 import org.graalvm.compiler.api.replacements.Snippet;
78 import org.graalvm.compiler.api.replacements.Snippet.ConstantParameter;
79 import org.graalvm.compiler.bytecode.Bytecode;
80 import org.graalvm.compiler.bytecode.ResolvedJavaMethodBytecode;
81 import org.graalvm.compiler.core.common.spi.ForeignCallDescriptor;
82 import org.graalvm.compiler.core.common.type.ObjectStamp;
83 import org.graalvm.compiler.core.common.type.StampFactory;
84 import org.graalvm.compiler.core.common.type.StampPair;
85 import org.graalvm.compiler.debug.DebugHandlersFactory;
86 import org.graalvm.compiler.graph.Node.ConstantNodeParameter;
87 import org.graalvm.compiler.graph.Node.NodeIntrinsic;
88 import org.graalvm.compiler.graph.iterators.NodeIterable;
89 import org.graalvm.compiler.hotspot.GraalHotSpotVMConfig;
90 import org.graalvm.compiler.hotspot.meta.HotSpotProviders;
91 import org.graalvm.compiler.hotspot.meta.HotSpotRegistersProvider;
92 import org.graalvm.compiler.hotspot.nodes.AcquiredCASLockNode;
93 import org.graalvm.compiler.hotspot.nodes.CurrentLockNode;
94 import org.graalvm.compiler.hotspot.nodes.FastAcquireBiasedLockNode;
95 import org.graalvm.compiler.hotspot.nodes.MonitorCounterNode;
96 import org.graalvm.compiler.hotspot.word.KlassPointer;
97 import org.graalvm.compiler.nodes.BreakpointNode;
98 import org.graalvm.compiler.nodes.CallTargetNode.InvokeKind;
99 import org.graalvm.compiler.nodes.ConstantNode;
100 import org.graalvm.compiler.nodes.DeoptimizeNode;
101 import org.graalvm.compiler.nodes.FrameState;
102 import org.graalvm.compiler.nodes.InvokeNode;
103 import org.graalvm.compiler.nodes.NamedLocationIdentity;
104 import org.graalvm.compiler.nodes.NodeView;
105 import org.graalvm.compiler.nodes.ReturnNode;
106 import org.graalvm.compiler.nodes.StructuredGraph;
107 import org.graalvm.compiler.nodes.ValueNode;
108 import org.graalvm.compiler.nodes.debug.DynamicCounterNode;
109 import org.graalvm.compiler.nodes.extended.ForeignCallNode;
110 import org.graalvm.compiler.nodes.extended.MembarNode;
111 import org.graalvm.compiler.nodes.java.MethodCallTargetNode;
112 import org.graalvm.compiler.nodes.java.MonitorExitNode;
113 import org.graalvm.compiler.nodes.java.RawMonitorEnterNode;
114 import org.graalvm.compiler.nodes.spi.LoweringTool;
115 import org.graalvm.compiler.nodes.type.StampTool;
116 import org.graalvm.compiler.options.OptionValues;
117 import org.graalvm.compiler.phases.common.inlining.InliningUtil;
118 import org.graalvm.compiler.replacements.Log;
119 import org.graalvm.compiler.replacements.SnippetCounter;
120 import org.graalvm.compiler.replacements.SnippetTemplate.AbstractTemplates;
121 import org.graalvm.compiler.replacements.SnippetTemplate.Arguments;
122 import org.graalvm.compiler.replacements.SnippetTemplate.SnippetInfo;
123 import org.graalvm.compiler.replacements.Snippets;
124 import org.graalvm.compiler.word.Word;
125 import jdk.internal.vm.compiler.word.LocationIdentity;
126 import jdk.internal.vm.compiler.word.Pointer;
127 import jdk.internal.vm.compiler.word.WordBase;
128 import jdk.internal.vm.compiler.word.WordFactory;
129
130 import jdk.vm.ci.code.BytecodeFrame;
131 import jdk.vm.ci.code.Register;
132 import jdk.vm.ci.code.TargetDescription;
133 import jdk.vm.ci.meta.DeoptimizationAction;
134 import jdk.vm.ci.meta.DeoptimizationReason;
135 import jdk.vm.ci.meta.JavaType;
136 import jdk.vm.ci.meta.ResolvedJavaType;
137
138 /**
139 * Snippets used for implementing the monitorenter and monitorexit instructions.
140 *
141 * The locking algorithm used is described in the paper
142 * <a href="http://dl.acm.org/citation.cfm?id=1167515.1167496"> Eliminating synchronization-related
143 * atomic operations with biased locking and bulk rebiasing</a> by Kenneth Russell and David
144 * Detlefs.
145 *
146 * Comment below is reproduced from {@code markOop.hpp} for convenience:
147 *
148 * <pre>
149 * Bit-format of an object header (most significant first, big endian layout below):
150 * 32 bits:
151 * --------
152 * hash:25 ------------>| age:4 biased_lock:1 lock:2 (normal object)
153 * JavaThread*:23 epoch:2 age:4 biased_lock:1 lock:2 (biased object)
154 * size:32 ------------------------------------------>| (CMS free block)
155 * PromotedObject*:29 ---------->| promo_bits:3 ----->| (CMS promoted object)
156 *
157 * 64 bits:
158 * --------
159 * unused:25 hash:31 -->| unused:1 age:4 biased_lock:1 lock:2 (normal object)
160 * JavaThread*:54 epoch:2 unused:1 age:4 biased_lock:1 lock:2 (biased object)
161 * PromotedObject*:61 --------------------->| promo_bits:3 ----->| (CMS promoted object)
162 * size:64 ----------------------------------------------------->| (CMS free block)
163 *
164 * unused:25 hash:31 -->| cms_free:1 age:4 biased_lock:1 lock:2 (COOPs && normal object)
165 * JavaThread*:54 epoch:2 cms_free:1 age:4 biased_lock:1 lock:2 (COOPs && biased object)
166 * narrowOop:32 unused:24 cms_free:1 unused:4 promo_bits:3 ----->| (COOPs && CMS promoted object)
167 * unused:21 size:35 -->| cms_free:1 unused:7 ------------------>| (COOPs && CMS free block)
168 *
169 * - hash contains the identity hash value: largest value is
170 * 31 bits, see os::random(). Also, 64-bit vm's require
171 * a hash value no bigger than 32 bits because they will not
172 * properly generate a mask larger than that: see library_call.cpp
173 * and c1_CodePatterns_sparc.cpp.
174 *
175 * - the biased lock pattern is used to bias a lock toward a given
176 * thread. When this pattern is set in the low three bits, the lock
177 * is either biased toward a given thread or "anonymously" biased,
178 * indicating that it is possible for it to be biased. When the
179 * lock is biased toward a given thread, locking and unlocking can
180 * be performed by that thread without using atomic operations.
181 * When a lock's bias is revoked, it reverts back to the normal
182 * locking scheme described below.
183 *
184 * Note that we are overloading the meaning of the "unlocked" state
185 * of the header. Because we steal a bit from the age we can
186 * guarantee that the bias pattern will never be seen for a truly
187 * unlocked object.
188 *
189 * Note also that the biased state contains the age bits normally
190 * contained in the object header. Large increases in scavenge
191 * times were seen when these bits were absent and an arbitrary age
192 * assigned to all biased objects, because they tended to consume a
193 * significant fraction of the eden semispaces and were not
194 * promoted promptly, causing an increase in the amount of copying
195 * performed. The runtime system aligns all JavaThread* pointers to
196 * a very large value (currently 128 bytes (32bVM) or 256 bytes (64bVM))
197 * to make room for the age bits & the epoch bits (used in support of
198 * biased locking), and for the CMS "freeness" bit in the 64bVM (+COOPs).
199 *
200 * [JavaThread* | epoch | age | 1 | 01] lock is biased toward given thread
201 * [0 | epoch | age | 1 | 01] lock is anonymously biased
202 *
203 * - the two lock bits are used to describe three states: locked/unlocked and monitor.
204 *
205 * [ptr | 00] locked ptr points to real header on stack
206 * [header | 0 | 01] unlocked regular object header
207 * [ptr | 10] monitor inflated lock (header is wapped out)
208 * [ptr | 11] marked used by markSweep to mark an object
209 * not valid at any other time
210 *
211 * We assume that stack/thread pointers have the lowest two bits cleared.
212 * </pre>
213 *
214 * Note that {@code Thread::allocate} enforces {@code JavaThread} objects to be aligned
215 * appropriately to comply with the layouts above.
216 */
217 public class MonitorSnippets implements Snippets {
218
219 private static final boolean PROFILE_CONTEXT = false;
220
221 @Fold
222 static boolean doProfile(OptionValues options) {
223 return ProfileMonitors.getValue(options);
224 }
225
226 @Snippet
227 public static void monitorenter(Object object, KlassPointer hub, @ConstantParameter int lockDepth, @ConstantParameter Register threadRegister, @ConstantParameter Register stackPointerRegister,
228 @ConstantParameter boolean trace, @ConstantParameter OptionValues options, @ConstantParameter Counters counters) {
229 verifyOop(object);
230
231 // Load the mark word - this includes a null-check on object
232 final Word mark = loadWordFromObject(object, markOffset(INJECTED_VMCONFIG));
233
234 final Word lock = beginLockScope(lockDepth);
235
236 Pointer objectPointer = Word.objectToTrackedPointer(object);
237 trace(trace, " object: 0x%016lx\n", objectPointer);
238 trace(trace, " lock: 0x%016lx\n", lock);
239 trace(trace, " mark: 0x%016lx\n", mark);
240
241 incCounter(options);
242
243 if (useBiasedLocking(INJECTED_VMCONFIG)) {
244 if (tryEnterBiased(object, hub, lock, mark, threadRegister, trace, options, counters)) {
245 return;
246 }
247 // not biased, fall-through
248 }
249 if (inlineFastLockSupported(options) && probability(SLOW_PATH_PROBABILITY, mark.and(monitorMask(INJECTED_VMCONFIG)).notEqual(0))) {
250 // Inflated case
251 if (tryEnterInflated(object, lock, mark, threadRegister, trace, options, counters)) {
252 return;
253 }
254 } else {
255 // Create the unlocked mark word pattern
256 Word unlockedMark = mark.or(unlockedMask(INJECTED_VMCONFIG));
257 trace(trace, " unlockedMark: 0x%016lx\n", unlockedMark);
258
259 // Copy this unlocked mark word into the lock slot on the stack
260 lock.writeWord(lockDisplacedMarkOffset(INJECTED_VMCONFIG), unlockedMark, DISPLACED_MARK_WORD_LOCATION);
261
262 // make sure previous store does not float below compareAndSwap
263 MembarNode.memoryBarrier(STORE_STORE);
264
265 // Test if the object's mark word is unlocked, and if so, store the
266 // (address of) the lock slot into the object's mark word.
267 Word currentMark = objectPointer.compareAndSwapWord(markOffset(INJECTED_VMCONFIG), unlockedMark, lock, MARK_WORD_LOCATION);
268 if (probability(FAST_PATH_PROBABILITY, currentMark.equal(unlockedMark))) {
269 traceObject(trace, "+lock{cas}", object, true, options);
270 counters.lockCas.inc();
271 AcquiredCASLockNode.mark(object);
272 return;
273 } else {
274 trace(trace, " currentMark: 0x%016lx\n", currentMark);
275 // The mark word in the object header was not the same.
276 // Either the object is locked by another thread or is already locked
277 // by the current thread. The latter is true if the mark word
278 // is a stack pointer into the current thread's stack, i.e.:
279 //
280 // 1) (currentMark & aligned_mask) == 0
281 // 2) rsp <= currentMark
282 // 3) currentMark <= rsp + page_size
283 //
284 // These 3 tests can be done by evaluating the following expression:
285 //
286 // (currentMark - rsp) & (aligned_mask - page_size)
287 //
288 // assuming both the stack pointer and page_size have their least
289 // significant 2 bits cleared and page_size is a power of 2
290 final Word alignedMask = WordFactory.unsigned(wordSize() - 1);
291 final Word stackPointer = registerAsWord(stackPointerRegister).add(config(INJECTED_VMCONFIG).stackBias);
292 if (probability(FAST_PATH_PROBABILITY, currentMark.subtract(stackPointer).and(alignedMask.subtract(pageSize())).equal(0))) {
293 // Recursively locked => write 0 to the lock slot
294 lock.writeWord(lockDisplacedMarkOffset(INJECTED_VMCONFIG), WordFactory.zero(), DISPLACED_MARK_WORD_LOCATION);
295 traceObject(trace, "+lock{cas:recursive}", object, true, options);
296 counters.lockCasRecursive.inc();
297 return;
298 }
299 traceObject(trace, "+lock{stub:failed-cas/stack}", object, true, options);
300 counters.lockStubFailedCas.inc();
301 }
302 }
303 // slow-path runtime-call
304 monitorenterStubC(MONITORENTER, object, lock);
305 }
306
307 private static boolean tryEnterBiased(Object object, KlassPointer hub, Word lock, Word mark, Register threadRegister, boolean trace, OptionValues options, Counters counters) {
308 // See whether the lock is currently biased toward our thread and
309 // whether the epoch is still valid.
310 // Note that the runtime guarantees sufficient alignment of JavaThread
311 // pointers to allow age to be placed into low bits.
312 final Word biasableLockBits = mark.and(biasedLockMaskInPlace(INJECTED_VMCONFIG));
313
314 // Check whether the bias pattern is present in the object's mark word
315 // and the bias owner and the epoch are both still current.
316 final Word prototypeMarkWord = hub.readWord(prototypeMarkWordOffset(INJECTED_VMCONFIG), PROTOTYPE_MARK_WORD_LOCATION);
317 final Word thread = registerAsWord(threadRegister);
318 final Word tmp = prototypeMarkWord.or(thread).xor(mark).and(~ageMaskInPlace(INJECTED_VMCONFIG));
319 trace(trace, "prototypeMarkWord: 0x%016lx\n", prototypeMarkWord);
320 trace(trace, " thread: 0x%016lx\n", thread);
321 trace(trace, " tmp: 0x%016lx\n", tmp);
322 if (probability(FAST_PATH_PROBABILITY, tmp.equal(0))) {
323 // Object is already biased to current thread -> done
324 traceObject(trace, "+lock{bias:existing}", object, true, options);
325 counters.lockBiasExisting.inc();
326 FastAcquireBiasedLockNode.mark(object);
327 return true;
328 }
329
330 // Now check to see whether biasing is enabled for this object
331 if (probability(NOT_FREQUENT_PROBABILITY, biasableLockBits.equal(WordFactory.unsigned(biasedLockPattern(INJECTED_VMCONFIG))))) {
332 Pointer objectPointer = Word.objectToTrackedPointer(object);
333 // At this point we know that the mark word has the bias pattern and
334 // that we are not the bias owner in the current epoch. We need to
335 // figure out more details about the state of the mark word in order to
336 // know what operations can be legally performed on the object's
337 // mark word.
338
339 // If the low three bits in the xor result aren't clear, that means
340 // the prototype header is no longer biasable and we have to revoke
341 // the bias on this object.
342 if (probability(FREQUENT_PROBABILITY, tmp.and(biasedLockMaskInPlace(INJECTED_VMCONFIG)).equal(0))) {
343 // Biasing is still enabled for object's type. See whether the
344 // epoch of the current bias is still valid, meaning that the epoch
345 // bits of the mark word are equal to the epoch bits of the
346 // prototype mark word. (Note that the prototype mark word's epoch bits
347 // only change at a safepoint.) If not, attempt to rebias the object
348 // toward the current thread. Note that we must be absolutely sure
349 // that the current epoch is invalid in order to do this because
350 // otherwise the manipulations it performs on the mark word are
351 // illegal.
352 if (probability(FREQUENT_PROBABILITY, tmp.and(epochMaskInPlace(INJECTED_VMCONFIG)).equal(0))) {
353 // The epoch of the current bias is still valid but we know nothing
354 // about the owner; it might be set or it might be clear. Try to
355 // acquire the bias of the object using an atomic operation. If this
356 // fails we will go in to the runtime to revoke the object's bias.
357 // Note that we first construct the presumed unbiased header so we
358 // don't accidentally blow away another thread's valid bias.
359 Word unbiasedMark = mark.and(biasedLockMaskInPlace(INJECTED_VMCONFIG) | ageMaskInPlace(INJECTED_VMCONFIG) | epochMaskInPlace(INJECTED_VMCONFIG));
360 Word biasedMark = unbiasedMark.or(thread);
361 trace(trace, " unbiasedMark: 0x%016lx\n", unbiasedMark);
362 trace(trace, " biasedMark: 0x%016lx\n", biasedMark);
363 if (probability(VERY_FAST_PATH_PROBABILITY, objectPointer.logicCompareAndSwapWord(markOffset(INJECTED_VMCONFIG), unbiasedMark, biasedMark, MARK_WORD_LOCATION))) {
364 // Object is now biased to current thread -> done
365 traceObject(trace, "+lock{bias:acquired}", object, true, options);
366 counters.lockBiasAcquired.inc();
367 return true;
368 }
369 // If the biasing toward our thread failed, this means that another thread
370 // owns the bias and we need to revoke that bias. The revocation will occur
371 // in the interpreter runtime.
372 traceObject(trace, "+lock{stub:revoke}", object, true, options);
373 counters.lockStubRevoke.inc();
374 } else {
375 // At this point we know the epoch has expired, meaning that the
376 // current bias owner, if any, is actually invalid. Under these
377 // circumstances _only_, are we allowed to use the current mark word
378 // value as the comparison value when doing the CAS to acquire the
379 // bias in the current epoch. In other words, we allow transfer of
380 // the bias from one thread to another directly in this situation.
381 Word biasedMark = prototypeMarkWord.or(thread);
382 trace(trace, " biasedMark: 0x%016lx\n", biasedMark);
383 if (probability(VERY_FAST_PATH_PROBABILITY, objectPointer.logicCompareAndSwapWord(markOffset(INJECTED_VMCONFIG), mark, biasedMark, MARK_WORD_LOCATION))) {
384 // Object is now biased to current thread -> done
385 traceObject(trace, "+lock{bias:transfer}", object, true, options);
386 counters.lockBiasTransfer.inc();
387 return true;
388 }
389 // If the biasing toward our thread failed, then another thread
390 // succeeded in biasing it toward itself and we need to revoke that
391 // bias. The revocation will occur in the runtime in the slow case.
392 traceObject(trace, "+lock{stub:epoch-expired}", object, true, options);
393 counters.lockStubEpochExpired.inc();
394 }
395 // slow-path runtime-call
396 monitorenterStubC(MONITORENTER, object, lock);
397 return true;
398 } else {
399 // The prototype mark word doesn't have the bias bit set any
400 // more, indicating that objects of this data type are not supposed
401 // to be biased any more. We are going to try to reset the mark of
402 // this object to the prototype value and fall through to the
403 // CAS-based locking scheme. Note that if our CAS fails, it means
404 // that another thread raced us for the privilege of revoking the
405 // bias of this particular object, so it's okay to continue in the
406 // normal locking code.
407 Word result = objectPointer.compareAndSwapWord(markOffset(INJECTED_VMCONFIG), mark, prototypeMarkWord, MARK_WORD_LOCATION);
408
409 // Fall through to the normal CAS-based lock, because no matter what
410 // the result of the above CAS, some thread must have succeeded in
411 // removing the bias bit from the object's header.
412
413 if (ENABLE_BREAKPOINT) {
414 bkpt(object, mark, tmp, result);
415 }
416 counters.revokeBias.inc();
417 return false;
418 }
419 } else {
420 // Biasing not enabled -> fall through to lightweight locking
421 counters.unbiasable.inc();
422 return false;
423 }
424 }
425
426 @Fold
427 public static boolean useFastInflatedLocking(OptionValues options) {
428 return SimpleFastInflatedLocking.getValue(options);
429 }
430
431 private static boolean inlineFastLockSupported(OptionValues options) {
432 return inlineFastLockSupported(INJECTED_VMCONFIG, options);
433 }
434
435 private static boolean inlineFastLockSupported(GraalHotSpotVMConfig config, OptionValues options) {
436 return useFastInflatedLocking(options) && monitorMask(config) >= 0 && objectMonitorOwnerOffset(config) >= 0;
437 }
438
439 private static boolean tryEnterInflated(Object object, Word lock, Word mark, Register threadRegister, boolean trace, OptionValues options, Counters counters) {
440 // write non-zero value to lock slot
441 lock.writeWord(lockDisplacedMarkOffset(INJECTED_VMCONFIG), lock, DISPLACED_MARK_WORD_LOCATION);
442 // mark is a pointer to the ObjectMonitor + monitorMask
443 Word monitor = mark.subtract(monitorMask(INJECTED_VMCONFIG));
444 int ownerOffset = objectMonitorOwnerOffset(INJECTED_VMCONFIG);
445 Word owner = monitor.readWord(ownerOffset, OBJECT_MONITOR_OWNER_LOCATION);
446 if (probability(FREQUENT_PROBABILITY, owner.equal(0))) {
447 // it appears unlocked (owner == 0)
448 if (probability(FREQUENT_PROBABILITY, monitor.logicCompareAndSwapWord(ownerOffset, owner, registerAsWord(threadRegister), OBJECT_MONITOR_OWNER_LOCATION))) {
449 // success
450 traceObject(trace, "+lock{inflated:cas}", object, true, options);
451 counters.inflatedCas.inc();
452 return true;
453 } else {
454 traceObject(trace, "+lock{stub:inflated:failed-cas}", object, true, options);
455 counters.inflatedFailedCas.inc();
456 }
457 } else {
458 traceObject(trace, "+lock{stub:inflated:owned}", object, true, options);
459 counters.inflatedOwned.inc();
460 }
461 return false;
462 }
463
464 /**
465 * Calls straight out to the monitorenter stub.
466 */
467 @Snippet
468 public static void monitorenterStub(Object object, @ConstantParameter int lockDepth, @ConstantParameter boolean trace, @ConstantParameter OptionValues options) {
469 verifyOop(object);
470 incCounter(options);
471 if (object == null) {
472 DeoptimizeNode.deopt(DeoptimizationAction.InvalidateReprofile, DeoptimizationReason.NullCheckException);
473 }
474 // BeginLockScope nodes do not read from object so a use of object
475 // cannot float about the null check above
476 final Word lock = beginLockScope(lockDepth);
477 traceObject(trace, "+lock{stub}", object, true, options);
478 monitorenterStubC(MONITORENTER, object, lock);
479 }
480
481 @Snippet
482 public static void monitorexit(Object object, @ConstantParameter int lockDepth, @ConstantParameter Register threadRegister, @ConstantParameter boolean trace,
483 @ConstantParameter OptionValues options, @ConstantParameter Counters counters) {
484 trace(trace, " object: 0x%016lx\n", Word.objectToTrackedPointer(object));
485 final Word mark = loadWordFromObject(object, markOffset(INJECTED_VMCONFIG));
486 if (useBiasedLocking(INJECTED_VMCONFIG)) {
487 // Check for biased locking unlock case, which is a no-op
488 // Note: we do not have to check the thread ID for two reasons.
489 // First, the interpreter checks for IllegalMonitorStateException at
490 // a higher level. Second, if the bias was revoked while we held the
491 // lock, the object could not be rebiased toward another thread, so
492 // the bias bit would be clear.
493 trace(trace, " mark: 0x%016lx\n", mark);
494 if (probability(FREQUENT_PROBABILITY, mark.and(biasedLockMaskInPlace(INJECTED_VMCONFIG)).equal(WordFactory.unsigned(biasedLockPattern(INJECTED_VMCONFIG))))) {
495 endLockScope();
496 decCounter(options);
497 traceObject(trace, "-lock{bias}", object, false, options);
498 counters.unlockBias.inc();
499 return;
500 }
501 }
502
503 final Word lock = CurrentLockNode.currentLock(lockDepth);
504
505 // Load displaced mark
506 final Word displacedMark = lock.readWord(lockDisplacedMarkOffset(INJECTED_VMCONFIG), DISPLACED_MARK_WORD_LOCATION);
507 trace(trace, " displacedMark: 0x%016lx\n", displacedMark);
508
509 if (probability(NOT_LIKELY_PROBABILITY, displacedMark.equal(0))) {
510 // Recursive locking => done
511 traceObject(trace, "-lock{recursive}", object, false, options);
512 counters.unlockCasRecursive.inc();
513 } else {
514 if (!tryExitInflated(object, mark, lock, threadRegister, trace, options, counters)) {
515 verifyOop(object);
516 // Test if object's mark word is pointing to the displaced mark word, and if so,
517 // restore
518 // the displaced mark in the object - if the object's mark word is not pointing to
519 // the displaced mark word, do unlocking via runtime call.
520 Pointer objectPointer = Word.objectToTrackedPointer(object);
521 if (probability(VERY_FAST_PATH_PROBABILITY, objectPointer.logicCompareAndSwapWord(markOffset(INJECTED_VMCONFIG), lock, displacedMark, MARK_WORD_LOCATION))) {
522 traceObject(trace, "-lock{cas}", object, false, options);
523 counters.unlockCas.inc();
524 } else {
525 // The object's mark word was not pointing to the displaced header
526 traceObject(trace, "-lock{stub}", object, false, options);
527 counters.unlockStub.inc();
528 monitorexitStubC(MONITOREXIT, object, lock);
529 }
530 }
531 }
532 endLockScope();
533 decCounter(options);
534 }
535
536 private static boolean inlineFastUnlockSupported(OptionValues options) {
537 return inlineFastUnlockSupported(INJECTED_VMCONFIG, options);
538 }
539
540 private static boolean inlineFastUnlockSupported(GraalHotSpotVMConfig config, OptionValues options) {
541 return useFastInflatedLocking(options) && objectMonitorEntryListOffset(config) >= 0 && objectMonitorCxqOffset(config) >= 0 && monitorMask(config) >= 0 &&
542 objectMonitorOwnerOffset(config) >= 0 && objectMonitorRecursionsOffset(config) >= 0;
543 }
544
545 private static boolean tryExitInflated(Object object, Word mark, Word lock, Register threadRegister, boolean trace, OptionValues options, Counters counters) {
546 if (!inlineFastUnlockSupported(options)) {
547 return false;
548 }
549 if (probability(SLOW_PATH_PROBABILITY, mark.and(monitorMask(INJECTED_VMCONFIG)).notEqual(0))) {
550 // Inflated case
551 // mark is a pointer to the ObjectMonitor + monitorMask
552 Word monitor = mark.subtract(monitorMask(INJECTED_VMCONFIG));
553 int ownerOffset = objectMonitorOwnerOffset(INJECTED_VMCONFIG);
554 Word owner = monitor.readWord(ownerOffset, OBJECT_MONITOR_OWNER_LOCATION);
555 int recursionsOffset = objectMonitorRecursionsOffset(INJECTED_VMCONFIG);
556 Word recursions = monitor.readWord(recursionsOffset, OBJECT_MONITOR_RECURSION_LOCATION);
557 Word thread = registerAsWord(threadRegister);
558 if (probability(FAST_PATH_PROBABILITY, owner.xor(thread).or(recursions).equal(0))) {
559 // owner == thread && recursions == 0
560 int cxqOffset = objectMonitorCxqOffset(INJECTED_VMCONFIG);
561 Word cxq = monitor.readWord(cxqOffset, OBJECT_MONITOR_CXQ_LOCATION);
562 int entryListOffset = objectMonitorEntryListOffset(INJECTED_VMCONFIG);
563 Word entryList = monitor.readWord(entryListOffset, OBJECT_MONITOR_ENTRY_LIST_LOCATION);
564 if (probability(FREQUENT_PROBABILITY, cxq.or(entryList).equal(0))) {
565 // cxq == 0 && entryList == 0
566 // Nobody is waiting, success
567 // release_store
568 MembarNode.memoryBarrier(LOAD_STORE | STORE_STORE);
569 monitor.writeWord(ownerOffset, WordFactory.zero());
570 traceObject(trace, "-lock{inflated:simple}", object, false, options);
571 counters.unlockInflatedSimple.inc();
572 return true;
573 }
574 }
575 counters.unlockStubInflated.inc();
576 traceObject(trace, "-lock{stub:inflated}", object, false, options);
577 monitorexitStubC(MONITOREXIT, object, lock);
578 return true;
579 }
580 return false;
581 }
582
583 /**
584 * Calls straight out to the monitorexit stub.
585 */
586 @Snippet
587 public static void monitorexitStub(Object object, @ConstantParameter int lockDepth, @ConstantParameter boolean trace, @ConstantParameter OptionValues options) {
588 verifyOop(object);
589 traceObject(trace, "-lock{stub}", object, false, options);
590 final Word lock = CurrentLockNode.currentLock(lockDepth);
591 monitorexitStubC(MONITOREXIT, object, lock);
592 endLockScope();
593 decCounter(options);
594 }
595
596 public static void traceObject(boolean enabled, String action, Object object, boolean enter, OptionValues options) {
597 if (doProfile(options)) {
598 DynamicCounterNode.counter(enter ? "number of monitor enters" : "number of monitor exits", action, 1, PROFILE_CONTEXT);
599 }
600 if (enabled) {
601 Log.print(action);
602 Log.print(' ');
603 Log.printlnObject(object);
604 }
605 }
606
607 public static void trace(boolean enabled, String format, WordBase value) {
608 if (enabled) {
609 Log.printf(format, value.rawValue());
610 }
611 }
612
613 /**
614 * Leaving the breakpoint code in to provide an example of how to use the {@link BreakpointNode}
615 * intrinsic.
616 */
617 private static final boolean ENABLE_BREAKPOINT = false;
618
619 private static final LocationIdentity MONITOR_COUNTER_LOCATION = NamedLocationIdentity.mutable("MonitorCounter");
620
621 @NodeIntrinsic(BreakpointNode.class)
622 static native void bkpt(Object object, Word mark, Word tmp, Word value);
623
624 @Fold
625 static boolean verifyBalancedMonitors(OptionValues options) {
626 return VerifyBalancedMonitors.getValue(options);
627 }
628
629 public static void incCounter(OptionValues options) {
630 if (verifyBalancedMonitors(options)) {
631 final Word counter = MonitorCounterNode.counter();
632 final int count = counter.readInt(0, MONITOR_COUNTER_LOCATION);
633 counter.writeInt(0, count + 1, MONITOR_COUNTER_LOCATION);
634 }
635 }
636
637 public static void decCounter(OptionValues options) {
638 if (verifyBalancedMonitors(options)) {
639 final Word counter = MonitorCounterNode.counter();
640 final int count = counter.readInt(0, MONITOR_COUNTER_LOCATION);
641 counter.writeInt(0, count - 1, MONITOR_COUNTER_LOCATION);
642 }
643 }
644
645 @Snippet
646 private static void initCounter() {
647 final Word counter = MonitorCounterNode.counter();
648 counter.writeInt(0, 0, MONITOR_COUNTER_LOCATION);
649 }
650
651 @Snippet
652 private static void checkCounter(@ConstantParameter String errMsg) {
653 final Word counter = MonitorCounterNode.counter();
654 final int count = counter.readInt(0, MONITOR_COUNTER_LOCATION);
655 if (count != 0) {
656 vmError(errMsg, count);
657 }
658 }
659
660 public static class Counters {
661 /**
662 * Counters for the various paths for acquiring a lock. The counters whose names start with
663 * {@code "lock"} are mutually exclusive. The other counters are for paths that may be
664 * shared.
665 */
666 public final SnippetCounter lockBiasExisting;
667 public final SnippetCounter lockBiasAcquired;
668 public final SnippetCounter lockBiasTransfer;
669 public final SnippetCounter lockCas;
670 public final SnippetCounter lockCasRecursive;
671 public final SnippetCounter lockStubEpochExpired;
672 public final SnippetCounter lockStubRevoke;
673 public final SnippetCounter lockStubFailedCas;
674 public final SnippetCounter inflatedCas;
675 public final SnippetCounter inflatedFailedCas;
676 public final SnippetCounter inflatedOwned;
677 public final SnippetCounter unbiasable;
678 public final SnippetCounter revokeBias;
679
680 /**
681 * Counters for the various paths for releasing a lock. The counters whose names start with
682 * {@code "unlock"} are mutually exclusive. The other counters are for paths that may be
683 * shared.
684 */
685 public final SnippetCounter unlockBias;
686 public final SnippetCounter unlockCas;
687 public final SnippetCounter unlockCasRecursive;
688 public final SnippetCounter unlockStub;
689 public final SnippetCounter unlockStubInflated;
690 public final SnippetCounter unlockInflatedSimple;
691
692 public Counters(SnippetCounter.Group.Factory factory) {
693 SnippetCounter.Group enter = factory.createSnippetCounterGroup("MonitorEnters");
694 SnippetCounter.Group exit = factory.createSnippetCounterGroup("MonitorExits");
695 lockBiasExisting = new SnippetCounter(enter, "lock{bias:existing}", "bias-locked previously biased object");
696 lockBiasAcquired = new SnippetCounter(enter, "lock{bias:acquired}", "bias-locked newly biased object");
697 lockBiasTransfer = new SnippetCounter(enter, "lock{bias:transfer}", "bias-locked, biased transferred");
698 lockCas = new SnippetCounter(enter, "lock{cas}", "cas-locked an object");
699 lockCasRecursive = new SnippetCounter(enter, "lock{cas:recursive}", "cas-locked, recursive");
700 lockStubEpochExpired = new SnippetCounter(enter, "lock{stub:epoch-expired}", "stub-locked, epoch expired");
701 lockStubRevoke = new SnippetCounter(enter, "lock{stub:revoke}", "stub-locked, biased revoked");
702 lockStubFailedCas = new SnippetCounter(enter, "lock{stub:failed-cas/stack}", "stub-locked, failed cas and stack locking");
703 inflatedCas = new SnippetCounter(enter, "lock{inflated:cas}", "heavyweight-locked, cas-locked");
704 inflatedFailedCas = new SnippetCounter(enter, "lock{inflated:failed-cas}", "heavyweight-locked, failed cas");
705 inflatedOwned = new SnippetCounter(enter, "lock{inflated:owned}", "heavyweight-locked, already owned");
706 unbiasable = new SnippetCounter(enter, "unbiasable", "object with unbiasable type");
707 revokeBias = new SnippetCounter(enter, "revokeBias", "object had bias revoked");
708
709 unlockBias = new SnippetCounter(exit, "unlock{bias}", "bias-unlocked an object");
710 unlockCas = new SnippetCounter(exit, "unlock{cas}", "cas-unlocked an object");
711 unlockCasRecursive = new SnippetCounter(exit, "unlock{cas:recursive}", "cas-unlocked an object, recursive");
712 unlockStub = new SnippetCounter(exit, "unlock{stub}", "stub-unlocked an object");
713 unlockStubInflated = new SnippetCounter(exit, "unlock{stub:inflated}", "stub-unlocked an object with inflated monitor");
714 unlockInflatedSimple = new SnippetCounter(exit, "unlock{inflated}", "unlocked an object monitor");
715 }
716 }
717
718 public static class Templates extends AbstractTemplates {
719
720 private final SnippetInfo monitorenter = snippet(MonitorSnippets.class, "monitorenter");
721 private final SnippetInfo monitorexit = snippet(MonitorSnippets.class, "monitorexit");
722 private final SnippetInfo monitorenterStub = snippet(MonitorSnippets.class, "monitorenterStub");
723 private final SnippetInfo monitorexitStub = snippet(MonitorSnippets.class, "monitorexitStub");
724 private final SnippetInfo initCounter = snippet(MonitorSnippets.class, "initCounter");
725 private final SnippetInfo checkCounter = snippet(MonitorSnippets.class, "checkCounter");
726
727 private final boolean useFastLocking;
728 public final Counters counters;
729
730 public Templates(OptionValues options, Iterable<DebugHandlersFactory> factories, SnippetCounter.Group.Factory factory, HotSpotProviders providers, TargetDescription target,
731 boolean useFastLocking) {
732 super(options, factories, providers, providers.getSnippetReflection(), target);
733 this.useFastLocking = useFastLocking;
734
735 this.counters = new Counters(factory);
736 }
737
738 public void lower(RawMonitorEnterNode monitorenterNode, HotSpotRegistersProvider registers, LoweringTool tool) {
739 StructuredGraph graph = monitorenterNode.graph();
740 checkBalancedMonitors(graph, tool);
741
742 assert ((ObjectStamp) monitorenterNode.object().stamp(NodeView.DEFAULT)).nonNull();
743
744 Arguments args;
745 if (useFastLocking) {
746 args = new Arguments(monitorenter, graph.getGuardsStage(), tool.getLoweringStage());
747 args.add("object", monitorenterNode.object());
748 args.add("hub", monitorenterNode.getHub());
749 args.addConst("lockDepth", monitorenterNode.getMonitorId().getLockDepth());
750 args.addConst("threadRegister", registers.getThreadRegister());
751 args.addConst("stackPointerRegister", registers.getStackPointerRegister());
752 args.addConst("trace", isTracingEnabledForType(monitorenterNode.object()) || isTracingEnabledForMethod(graph));
753 args.addConst("options", graph.getOptions());
754 args.addConst("counters", counters);
755 } else {
756 args = new Arguments(monitorenterStub, graph.getGuardsStage(), tool.getLoweringStage());
757 args.add("object", monitorenterNode.object());
758 args.addConst("lockDepth", monitorenterNode.getMonitorId().getLockDepth());
759 args.addConst("trace", isTracingEnabledForType(monitorenterNode.object()) || isTracingEnabledForMethod(graph));
760 args.addConst("options", graph.getOptions());
761 args.addConst("counters", counters);
762 }
763
764 template(monitorenterNode, args).instantiate(providers.getMetaAccess(), monitorenterNode, DEFAULT_REPLACER, args);
765 }
766
767 public void lower(MonitorExitNode monitorexitNode, HotSpotRegistersProvider registers, LoweringTool tool) {
768 StructuredGraph graph = monitorexitNode.graph();
769
770 Arguments args;
771 if (useFastLocking) {
772 args = new Arguments(monitorexit, graph.getGuardsStage(), tool.getLoweringStage());
773 } else {
774 args = new Arguments(monitorexitStub, graph.getGuardsStage(), tool.getLoweringStage());
775 }
776 args.add("object", monitorexitNode.object());
777 args.addConst("lockDepth", monitorexitNode.getMonitorId().getLockDepth());
778 args.addConst("threadRegister", registers.getThreadRegister());
779 args.addConst("trace", isTracingEnabledForType(monitorexitNode.object()) || isTracingEnabledForMethod(graph));
780 args.addConst("options", graph.getOptions());
781 args.addConst("counters", counters);
782
783 template(monitorexitNode, args).instantiate(providers.getMetaAccess(), monitorexitNode, DEFAULT_REPLACER, args);
784 }
785
786 public static boolean isTracingEnabledForType(ValueNode object) {
787 ResolvedJavaType type = StampTool.typeOrNull(object.stamp(NodeView.DEFAULT));
788 String filter = TraceMonitorsTypeFilter.getValue(object.getOptions());
789 if (filter == null) {
790 return false;
791 } else {
792 if (filter.length() == 0) {
793 return true;
794 }
795 if (type == null) {
796 return false;
797 }
798 return (type.getName().contains(filter));
799 }
800 }
801
802 public static boolean isTracingEnabledForMethod(StructuredGraph graph) {
803 String filter = TraceMonitorsMethodFilter.getValue(graph.getOptions());
804 if (filter == null) {
805 return false;
806 } else {
807 if (filter.length() == 0) {
808 return true;
809 }
810 if (graph.method() == null) {
811 return false;
812 }
813 return (graph.method().format("%H.%n").contains(filter));
814 }
815 }
816
817 /**
818 * If balanced monitor checking is enabled then nodes are inserted at the start and all
819 * return points of the graph to initialize and check the monitor counter respectively.
820 */
821 private void checkBalancedMonitors(StructuredGraph graph, LoweringTool tool) {
822 if (VerifyBalancedMonitors.getValue(options)) {
823 NodeIterable<MonitorCounterNode> nodes = graph.getNodes().filter(MonitorCounterNode.class);
824 if (nodes.isEmpty()) {
825 // Only insert the nodes if this is the first monitorenter being lowered.
826 JavaType returnType = initCounter.getMethod().getSignature().getReturnType(initCounter.getMethod().getDeclaringClass());
827 StampPair returnStamp = StampFactory.forDeclaredType(graph.getAssumptions(), returnType, false);
828 MethodCallTargetNode callTarget = graph.add(new MethodCallTargetNode(InvokeKind.Static, initCounter.getMethod(), new ValueNode[0], returnStamp, null));
829 InvokeNode invoke = graph.add(new InvokeNode(callTarget, 0));
830 invoke.setStateAfter(graph.start().stateAfter());
831 graph.addAfterFixed(graph.start(), invoke);
832
833 StructuredGraph inlineeGraph = providers.getReplacements().getSnippet(initCounter.getMethod(), null, invoke.graph().trackNodeSourcePosition(), invoke.getNodeSourcePosition());
834 InliningUtil.inline(invoke, inlineeGraph, false, null);
835
836 List<ReturnNode> rets = graph.getNodes(ReturnNode.TYPE).snapshot();
837 for (ReturnNode ret : rets) {
838 returnType = checkCounter.getMethod().getSignature().getReturnType(checkCounter.getMethod().getDeclaringClass());
839 String msg = "unbalanced monitors in " + graph.method().format("%H.%n(%p)") + ", count = %d";
840 ConstantNode errMsg = ConstantNode.forConstant(tool.getConstantReflection().forString(msg), providers.getMetaAccess(), graph);
841 returnStamp = StampFactory.forDeclaredType(graph.getAssumptions(), returnType, false);
842 callTarget = graph.add(new MethodCallTargetNode(InvokeKind.Static, checkCounter.getMethod(), new ValueNode[]{errMsg}, returnStamp, null));
843 invoke = graph.add(new InvokeNode(callTarget, 0));
844 Bytecode code = new ResolvedJavaMethodBytecode(graph.method());
845 FrameState stateAfter = new FrameState(null, code, BytecodeFrame.AFTER_BCI, new ValueNode[0], new ValueNode[0], 0, new ValueNode[0], null, false, false);
846 invoke.setStateAfter(graph.add(stateAfter));
847 graph.addBeforeFixed(ret, invoke);
848
849 Arguments args = new Arguments(checkCounter, graph.getGuardsStage(), tool.getLoweringStage());
850 args.addConst("errMsg", msg);
851 inlineeGraph = template(invoke, args).copySpecializedGraph(graph.getDebug());
852 InliningUtil.inline(invoke, inlineeGraph, false, null);
853 }
854 }
855 }
856 }
857 }
858
859 public static final ForeignCallDescriptor MONITORENTER = new ForeignCallDescriptor("monitorenter", void.class, Object.class, Word.class);
860 public static final ForeignCallDescriptor MONITOREXIT = new ForeignCallDescriptor("monitorexit", void.class, Object.class, Word.class);
861
862 @NodeIntrinsic(ForeignCallNode.class)
863 private static native void monitorenterStubC(@ConstantNodeParameter ForeignCallDescriptor descriptor, Object object, Word lock);
864
865 @NodeIntrinsic(ForeignCallNode.class)
866 public static native void monitorexitStubC(@ConstantNodeParameter ForeignCallDescriptor descriptor, Object object, Word lock);
867 }